Georges Wildenstein. "L'Abbé de Saint-Non, artiste et mécène." Gazette des beaux-arts, 6th ser., 54 (November 1959), p. 228, fig. 5, publishes the pastel (in a "private collection"), reading the date as 1779 and identifying the girls as Rosalie Fragonard and Marguerite Gérard; notes that most of the surviving copies by Saint-Non after Fragonard are based on works from about 1770.
Georges Wildenstein. The Paintings of Fragonard, Complete Edition. London, 1960, p. 305, mentions the pastel in cataloguing Fragonard's painting [MMA 53.61.5; cat. no. 476], "The Two Sisters, or Portrait of Rosalie Fragonard and her aunt, Marguerite Gérard"; notes that the pastel is in the Wildenstein Collection.
Elizabeth E. Gardner. "Four French Paintings from the Berwind Collection." Metropolitan Museum of Art Bulletin 20 (May 1962), p. 268, fig. 5, reads the date as 1779.
Gabriele Mandel in L'opera completa di Fragonard. Milan, 1972, p. 108, no. 501², ill., illustrates the pastel to suggest the larger composition of Fragonard's original.
Mary Ann Wurth Harris. "The Abbé de Saint-Non and His Pastel Copy of a Painting by Fragonard." Apollo 110 (July 1979), pp. 57–61, fig. 61, reads the date on the pastel unhesitatingly as 1770; refutes identification of the girls as Rosalie Fragonard and Marguerite Gérard, as Rosalie was born in 1769 and Marguerite did not come to live with the Fragonard family in Paris until 1775; also notes that there was a separation of nearly nine years in the ages of the two girls; thoroughly discusses the relationship of the pastel to Fragonard's painting.
Denys Sutton. Fragonard. Exh. cat., National Museum of Western Art. Tokyo, 1980, unpaginated, discussed under no. 77 (Fragonard's painting), repeats Harris's ideas [see Ref. 1979] but misquotes the date on the pastel as 1790.
Pierre Rosenberg. Fragonard. Exh. cat., The Metropolitan Museum of Art. New York, 1988, pp. 332, 334, ill., observes that 1779 is the date generally agreed on for the pastel, but notes that for stylistic reasons the painting cannot have been painted later than 1770; states that the pastel was sold in Nice on November 2 or 7, 1951.
Jennifer D. Milam. Fragonard's Playful Paintings: Visual Games in Rococo Art. Manchester, 2006, p. 102 n. 54.
Katharine Baetjer and Marjorie Shelley. "Pastel Portraits: Images of 18th-Century Europe." Metropolitan Museum of Art Bulletin 68 (Spring 2011), pp. 24–25, 27, no. 14, ill. (color).